FIG. 3.

Images of neurite growth in the collagen gel-filled network. A dorsal root ganglion (DRG) was placed within a collagen gel in the underlying explant channel and cultured for 4–5 days, at which time the networks were perfused with paraformaldehyde and then stained immunohistochemically for neurofilament proteins. (A) As shown in this confocal micrograph, neurites grew from the DRG and either continued in the explant channel or grew up and into the cross-channel of the overlying H-shaped network. (B) To measure the length of neurites in either direction, the growing end of neurites was identified from epifluorescence images taken with an inverted microscope with a 40× objective, and the length back to the intersection of the explant and cross-channels was determined based on the stage position and location within the image (scale bars: A=150 μm and B=75 μm). Reproduced with permission from Sundararaghavan et al., 2009.